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/*!
\page qmlanimation.html
\title QML Animation

Animation in QML is done by animating properties of objects. Properties of type
real, int, color, rect, point, and size can all be animated.

QML supports three different forms of animation - basic property animation,
transitions, and property behaviors.

\section1 Basic Property Animation

The simplest form of animation is directly using \l PropertyAnimation, which can animate all of the property
types listed above. If the property you are animating is a number or color, you can alternatively use
NumberAnimation or ColorAnimation. These elements don't add any additional functionality,
but will help enforce type correctness and are slightly more efficient.

A property animation can be specified as a value source. This is especially useful for repeating animations.

The following example creates a bouncing effect:
\qml
Rectangle {
    id: rect
    width: 120; height: 200;
    Image {
        id: img
        source: "qt-logo.png"
        x: 60-img.width/2
        y: 0
        y: SequentialAnimation {
            running: true
            repeat: true
            NumberAnimation { to: 200-img.height; easing: "easeOutBounce"; duration: 2000 }
            PauseAnimation { duration: 1000 }
            NumberAnimation { to: 0; easing: "easeOutQuad"; duration: 1000 }
        }
    }
}
\endqml

\image propanim.gif

A property animation can also be specified as a resource that is manipulated from script.

\qml
PropertyAnimation {
    id: animation
    target: image
    property: "scale"
    from: 1; to: .5
}
Image {
    id: image
    source: "image.png"
    MouseRegion {
        anchors.fill: parent
        onPressed: animation.start()
    }
}
\endqml

Animations can be joined into a group using SequentialAnimation and ParallelAnimation.

\target state-transitions
\section1 Transitions

QML transitions describe animations to perform when \l{qmlstates}{state} changes occur.

For example, a transition could describe how an item moves from its initial position to its new position:

\code
transitions: [
    Transition {
        NumberAnimation {
            properties: "x,y"
            easing: "easeOutBounce"
            duration: 200
        }
    }
]
\endcode

As you can see from the above example, transitions make use of the same basic animation classes introduced
above. However, you generally use a different set of properties when working with transitions. In the example,
no target or property has been specified. Instead, we have specified properties, which acts as a selector to
determine which property changes to animate; in this case, we will animate any x,y properties that have
changed on any objects.

QML transitions also selectors to determine which state changes a transition should apply to:

\code
Transition {
    from: "*"
    to: "details"
    ...
}
\endcode

Transitions can happen in parallel, in sequence, or in any combination of the two:

\code
Transition {
    from: "*"
    to: "MyState"
    reversible: true
    SequentialAnimation {
        ColorAnimation {
            property: "color"
            duration: 1000
        }
        PauseAnimation {
            duration: 1000
        }
        ParallelAnimation {
            NumberAnimation {
                duration: 1000
                easing: "easeOutBounce"
                target: box1
                properties: "x,y"
            }
            NumberAnimation {
                duration: 1000
                target: box2
                properties: "x,y"
            }
        }
    }
}
\endcode

\section1 Property Behaviors

A property behavior specifies a default animation to run whenever the property's value changes.

In the following snippet, we specify that we want the x position of redRect to be animated
whenever it changes. The animation will last 300 milliseconds and use an InOutQuad easing curve.

\qml
Rectangle {
    id: redRect
    color: "red"
    width: 100; height: 100
    x: Behavior { NumberAnimation { duration: 300; easing: "InOutQuad" } }
}
\endqml

To trigger this behavior, we could:
\list
\o Enter a state that changes x

\qml
State {
    name: "myState"
    PropertyChanges {
        target: redRect
        x: 200
        ...
    }
}
\endqml

\o Update x from a script

\qml
MouseRegion {
    ....
    onClicked: redRect.x = 24;
}
\endqml
\endlist

If x were bound to another property, triggering the binding would also trigger the behavior.

If a state change has a transition animation matching a property with a Behavior, the transition animation
will override the Behavior for that state change.

*/